The Light Detection and Ranging （LiDAR） has been widely used in forest inventory. It is quite difficulty to describe the complex vertical structures of forest using the terrestrial or Unmanned Aerial Vehicle （UAV） LiDAR or laser scanning， individually. The complete spatial structure of forest can be obtained by combing the Terrestrial Laser Scanning （TLS） and UAV Laser Scanning （ULS）. The TLS and ULS point cloud were registered and fused to extract the trunks of individual trees. The random Hough transform was used to fit the point cloud of the trunk in segments. The taper equation was fitted using the diameters of trunk segments and the differential quadrature method was used to calculate the volumes of individual trees. The volumes of individual trees were accumulate to get plot volume. Compared with the calculated value of the binary volume model， the results showed that the accuracy of calculating the volume of individual tree based on the fusion point cloud was better than that of the terrestrial point cloud， the R² can be increased by more than 2%， and the RMSE can be reduced by 0.01 m³. The R² and RMSE were 0.98 and 0.87m³ for the plot volume， which calculated by the combination of taper equation and differential quadrature method. Among them， the R² and RMSE of Cunninghamia lanceolata volume were 0.96 and 0.07 m³， for Eucalyptus， the R² and RMSE were 0.93 and 0.07 m³. Among the three types of plots： easu， medium， and difficult， the volume R² of Cunninghamia lanceolata and Eucalyptus in easy and medium plots were all above 0.94， the RMSE was about 0.07 m³， but the R² of the volume results in difficult plot was below 0.9. The TLS and ULS fusion point cloud can more finely measure the forest spatial structure， and better meet the needs of forest resource survey applications.